Catastrophic optical damage (COD) of high power laser diodes is a crucial factor limiting ultra high power lasers. The understanding of the COD process is essential to improve the endurance of the high power laser diodes. COD is observed as a process in which the active part of the laser diode is destroyed, forming characteristic defects, the so called dark line defects (DLDs). The DLDs are formed by arrays of dislocations generated during the laser operation. Local heating associated with non-radiative recombination is assumed to be at the origin of the COD process. A summary of the methods used to assess the COD, both in real time and post-mortem is presented. The main approaches developed in recent years to model the heat transport in the laser structures under non homogeneous temperature distribution are overviewed. Special emphasis is paid to the impact of the low dimensionality of QWs in two physical properties playing a major role in the COD process, namely, thermal conductivity and mechanical strength. A discussion about the impact of the nanoscale in both physical properties is presented. Finally, we summarize the main issues of the thermomechanical modelling of COD. Within this model the COD is launched when the local thermal stresses generated around the heat source overcome the yield stress of the active zone of the laser. The thermal runaway is related to the sharp decrease of the thermal conductivity once the onset of plasticity has been reached in the active zone of the laser.

/pdf/thermomechanical-issues-of-high-power-laser-diode-41s7rcju1e.pdf

Thermomechanical issues of high power laser diode catastrophic optical damage

Recently demonstrated CMOS circuits based on Ge nanowires (Ge-FET) promise sustained technology scaling because higher mobility Ge guarantees target ${I}_{\text {ON}}$ at a lower ${V}_{{\textit {DD}}}$ . Unfortunately, this promise is counterbalanced by the fact that Ge is a poor thermal conductor, thus, the thermal confinement of the surround-gate topology may exacerbate self-heating (SHE) and erode the intrinsic performance gain associated with the high channel mobility. In this paper, we use: 1) electrical and optical methods to, respectively, characterize channel and surface SHE of Ge-FET with various channel lengths ( ${L}_{\text {ch}}$ ), widths ( ${W}_{\text {ch}}$ ), and the number of the nanowires (NWs) (#NW); 2) interpret the results obtained by the 3-D thermal modeling, and compare theoretically the SHE in Ge-FET configured in various topologies, such as bulk FinFET, silicon-on-insulator FinFET, and gate-all-around NW-FET; and 3) embed the results in an electrothermal SPICE simulator to compare the performance of ring oscillators based on Ge-FET and Si-FET. Our results show that the existing Ge-FET (with an airgap) is thermally suboptimal, but once optimized, SHE in Ge-FET would be comparable to that of Si-FET. The results encourage sustained development of Ge-FETs.

Performance Potential of Ge CMOS Technology From a Material-Device-Circuit Perspective

Facet Passivation Process of High-Power Laser Diodes by Plasma Cleaning and ZnO Film

Abstract Recent intensive simulations have uncovered remarkable phenomena in stability diagrams of classical oscillators, for instance, quint points, parameter rings, and chiral structures of non-quantum origin. So far, their experimental observation has remained elusive. Here, using a simple electronic circuit, we report the experimental detection of five phases of oscillation spread around a quint point, an exceptional point where five oscillatory modes meet. This finding corroborates predictions of non-quantum chirality in the control parameter space of nonlinear oscillators governed by rate equations. 

https://link.springer.com/content/pdf/10.1140/epjp/s13360-021-02318-7.pdf

Experimental evidence of quint points and non-quantum chirality in a minimalist autonomous electronic oscillator

In semiconductor lasers, quantum well intermixing (QWI) with high selectivity using dielectrics often results in lower quantum efficiency. In this paper, we report on an investigation regarding the effect of thermally induced dielectric stress on the quantum efficiency of quantum well structures in impurity-free vacancy disordering (IFVD) process using photoluminescence and device characterization in conjunction with microscopy. SiO2 and Si x O2/SrF2 (versus SrF2) films were employed for the enhancement and suppression of QWI, respectively. Large intermixing selectivity of 75 nm (125 meV), consistent with the theoretical modeling results, with negligible effect on the suppression region characteristics, was obtained. Si x O2 layer compensates for the large thermal expansion coefficient mismatch of SrF2 with the semiconductor and mitigates the detrimental effects of SrF2 without sacrificing its QWI benefits. The bilayer dielectric approach dramatically improved the dielectric–semiconductor interface quality. Fabricated high power semiconductor lasers demonstrated high quantum efficiency in the lasing region using the bilayer dielectric film during the intermixing process. Our results reveal that stress engineering in IFVD is essential and the thermal stress can be controlled by engineering the dielectric strain opening new perspectives for QWI of photonic devices.

/pdf/conservation-of-quantum-efficiency-in-quantum-well-3zlmguaefh.pdf

Conservation of quantum efficiency in quantum well intermixing by stress engineering with dielectric bilayers

Diode laser fundamentals are discussed, followed by an elaborate discussion of problem-oriented design guidelines and techniques, and by a systematic treatment of the origins of laser degradation and a thorough exploration of the engineering means to enhance the optical strength of the laser. Stability criteria of critical laser characteristics and key laser robustness factors are discussed along with clear design considerations in the context of reliability engineering approaches and models, and typical programs for reliability tests and laser product qualifications. Novel, advanced diagnostic methods are reviewed to discuss, for the first time in detail in book literature, performanceand reliability-impacting factors such as temperature, stress and material instabilities.

Semiconductor Laser Engineering, Reliability and Diagnostics: A Practical Approach to High Power and Single Mode Devices

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

Peter W. Epperlein

Author Tools

Chat about Author

Papers

Semiconductor Laser Engineering, Reliability and Diagnostics: A Practical Approach to High Power and Single Mode Devices